1. Field of the Invention
The invention relates to a roller cooling and/or lubricating device for cold rolling mills for strip, in particular, thin strip rolling mills and foil rolling mills, comprising nozzle beams correlated with the individual rollers and mounted on side shields of the roll housings of one or more roll stands, the nozzle beams having spray nozzles mounted therein across the width of the rollers and being adjustable relative to the correlated rollers independent from one another transverse to the running direction of the rolled strip in planes that are parallel to the strip plane, for the purpose of controlling the strip tensile stress across the strip width by a change of the effective roll barrel diameter and/or by affecting the roller lubrication with a pressure-controlled and/or quantity-controlled and/or temperature-controlled supply of rolling oil or emulsions.
2. Description of the Related Art
The flatness control of the rolled strip in a cold rolling mill for strip, which is furnished with a roller cooling and/or lubricating device of the aforementioned kind known from German patent 34 19 261 C3,is based on a change of the spray pattern of the rolling oil sprayed onto the surface of the working rollers or the sprayed-on emulsions. The change of the spray pattern is effected by an adjustment of the nozzle beam, correlated with each one of the working rollers of the rolling mill, relative to the working roller independent of the respective other nozzle beams transverse to the strip running direction in a plane which is parallel to the strip plane and a pressure-controlled and/or quantity-controlled and/or temperature-controlled supply of rolling oil or emulsions.
Thin strip and foil strip, which are rolled on a four-high or six-high roll stand with the known flatness control, are characterized by a high quality with respect to dimensional precision and shape precision as well as flatness.
A disadvantage of roller cooling and/or lubricating devices of the aforementioned kind for cold rolling mills of strip is the insufficient accessibility of the nozzle beams with the spray nozzles and their corresponding control valves so that repair and maintenance work on the nozzle beams is cumbersome and time-consuming.
It is an object of the present invention to optimize the control of the strip flatness in cold rolling mills for strip by means of the aforementioned roller cooling and/or lubricating device in order to compensate undesirable strip tensile stress deviations within zones in the rolled strip and to improve the accessibility of the spray nozzles, installed in the nozzle beams of the roller cooling and/or lubricating device, and of their corresponding control valves with respect to a simplification and acceleration of required repair and maintenance work.
In accordance with the present invention, this is achieved in that:
a) the nozzle beams are movable by means of a linear drive (adjusting cylinders) in the direction of their longitudinal axis transverse to the running direction of the rolled strip and rotatable by means of a rotary drive about the longitudinal axis;
b) positioning devices are arranged on the roll stand or the roll stands for moving the nozzle beams from a roller-remote maintenance position into the working position at the rollers and from the working position into the maintenance position;
c) the control valves of the spray nozzles to be opened or closed are switched in a certain time frame with time delay;
d) the spray nozzles, which are mounted at identical spacing within the nozzle beams, have: a nozzle holder, which is inserted into corresponding openings in the front wall section facing a roller as well as the rear wall section of a nozzle beam, sealed relative to the nozzle beam, and penetrates the interior space thereof; moreover, a nozzle head, which is inserted into a bore in the forward end of the nozzle holder facing the roller, preferably is screwed into it, or which is placed onto the forward end of the nozzle holder, preferably screwed thereon, and which has at least one nozzle opening and an ante-chamber; a rotary slide valve which is supported in a central throughbore of the nozzle holder so as to be rotatable about the longitudinal axis of the spray nozzle and has a blind bore open toward the nozzle head and has in the area of the blind bore at least one inlet opening which, in the open position of the spray nozzle, is aligned with a corresponding inlet opening, open toward the interior space of the nozzle beam, of the nozzle holder or the nozzle head, and, in the closed position of the spray nozzle, is closed by a wall of the nozzle holder or the nozzle head; as well as a control member engaging the end of the rotary slide valve remote from the nozzle head.
The roller cooling and/or lubricating device has the following advantages.
The spray angle of the spray nozzles of the nozzle beams relative to the rollers, which is adjustable by rotating the nozzle beams about the longitudinal beam axis, provides a further parameter in addition to the adjustability of the nozzle beams relative to the respectively correlated roller transverse to the strip running direction as well as to the change of the quantity, the pressure, and the temperature of the rolling oil sprayed onto the rollers or the sprayed-on emulsions for changing the spray pattern on the roller surface within the context of a strip flatness control. The spray angle of the spray nozzles as an additional parameter makes possible an optimization of the strip flatness control. By rotating the nozzle beam by 180xc2x0, the spray nozzles can be moved in a simple way from the roller-proximal working position into a roller-remote maintenance position for a simple and fast performance of required maintenance and repair work. The positioning devices mounted on the roll stands make possible a simple movement of the nozzle beams from the working position at the rollers into a maintenance position remote therefrom in which all nozzle beams are easily accessible for repair and maintenance work. By the successive switching of the control valves of the spray nozzles to be opened or closed in a certain time frame with a time delay, the pressure in the cooling medium supply lines of the spray nozzles can be maintained substantially constant independent of the number of actuated nozzles so that liquid shocks as a result of pressure fluctuations, which can result in damage to the cooling medium lines and the control valves, are prevented. The rotary slide valve which is used for the spray nozzles of the roller cooling and/or lubricating device requires together with the control member, that, as a result of the small mass of the rotary slide valve, needs only a minimal control force, only little space so that the mounting space necessary across the strip width for each individual spray nozzle is significantly smaller in comparison to known roller cooling and/or lubricating devices, and the spray zone width of the spray nozzles is correspondingly reduced and, accordingly, the precision of the strip flatness control is significantly improved.
The invention will be explained in the following with the aid of schematic drawings of a roller cooling and/or lubricating device used in a four-high stand.